Method and apparatus for efficient storage and retrieval of multiple content streams

ABSTRACT

Embodiments of the present invention provide disk controller operable to facilitate the efficient storage and retrieval of multiple content (data) streams to magnetic disk media. This disk controller includes an interface module, a memory module, and a processing module. The interface module is operable to couple the disk controller to a hard disk drive. The memory module and processing module in combination are operable to execute instructions that detect the geometry associated with the hard disk drive. Then the disk controller is operable to determine when the hard disk drive geometry supports assigning unique RW heads to unique content (data) streams. When the hard disk geometry supports assigning unique RW heads to unique content (data) streams, RW heads may be preferentially reserved or assigned to unique content streams wherein the RW heads are able to write unique content streams to memory locations within the hard disk drive, wherein these memory locations may be contiguous or near contiguous.

TECHNICAL FIELD OF THE INVENTION

The present invention relates generally to magnetic disk media and moreparticularly to the storage and retrieval of content to magnetic diskmedia.

BACKGROUND OF THE INVENTION

Currently, magnetic media, such as hard disk drives are used to store(record) and retrieve (playback) multimedia content in Digital VideoRecorders (DVRs). While a hard disk drive may be quite efficient atstoring and playing back a single content stream, many limitations arisewhere two or more content streams require simultaneous access. Eachstream contains data that is best accessed from contiguous locationswithin the hard disk drive.

Contiguous storage of such content allows faster access and reducesfragmentation. However, since the data from two or more streams ismultiplexed and placed at random track locations within the hard diskdrive, the read write (RW) head has to continuously move betweendifferent sections of the disk to read or write this data.Alternatively, if the content received from the multiple channels isstored within a single contiguous section or contiguous block of thedisk.

The data (content) from the first channel (A) and second channel (B)alternates within the single memory location (contiguous section orblock of disk) creating a potentially serious fragmentation problem.This second mode of operation is typically within most disk subsystemswherein their host is blind to the internal geometry and organizationwithin the disk.

The structure and operation of hard disk drives is generally known. Harddisk drives include, generally, a case, a hard disk having magneticallyalterable properties, and a read/write mechanism including Read/Write(RW) heads operable to write data to the hard disk by locally alertingthe magnetic properties of the hard disk and to read data from the harddisk by reading local magnetic properties of the hard disk. The harddisk may include multiple platters, each platter being a planar disk.

All information stored on the hard disk is recorded in tracks, which areconcentric circles organized on the surface of the platters. FIG. 1depicts a pattern of radially-spaced concentric data tracks 12 within adisk 10. Data stored on the disks may be accessed by moving RW headsradially as driven by a head actuator to the radial location of thetrack containing the data. The track-based organization of data on thehard disk(s) allows for easy access to any part of the disk, which iswhy hard disk drives are called “random access” storage devices.

Since each track typically holds many thousands of bytes of data, thetracks are further divided into smaller units called sectors. Thisreduces the amount of space wasted by small files. Each sector holds 512bytes of user data, plus as many as a few dozen additional bytes usedfor internal drive control and for error detection and correction.

SUMMARY OF THE INVENTION

Embodiments of the present invention are directed to systems and methodsthat are further described in the following description and claims.Advantages and features of embodiments of the present invention maybecome apparent from the description, accompanying drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention and theadvantages thereof, reference is now made to the following descriptiontaken in conjunction with the accompanying drawings in which likereference numerals indicate like features and wherein:

FIG. 1 depicts a pattern of radially-spaced concentric data trackswithin the magnetic media of a disk;

FIG. 2 is a function block diagram of a digital content recorder;

FIG. 3 is a function block diagram of a digital content recorder;

FIG. 4 is a function block diagram of a hard disk drive;

FIG. 5 is a functional block diagram of a disk controller in accordancewith an embodiment of the present invention;

FIG. 6 is a functional diagram of a multi-platter disk drive utilizedwithin an embodiment of the present invention;

FIG. 7 is a diagram illustrating the writing of diverse content streamsto different platters within a cylinder of a hard disk drive inaccordance with an embodiment of the present invention;

FIG. 8 provides a functional block diagram of a data storage andretrieval system in accordance with an embodiment of the presentinvention;

FIG. 9 provides a functional block diagram of a content recorder inaccordance with an embodiment of the present invention;

FIG. 10 provides a logic flow diagram illustrating a method operable topreferentially assign RW heads to content streams in accordance with anembodiment of the present invention; and

FIG. 11 provides a logic flow diagram in accordance with an embodimentof the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the present invention are illustrated in theFIGUREs, like numerals being used to refer to like and correspondingparts of the various drawings.

The present invention provides a method and apparatus operable tosupport the efficient storage and retrieval of multiple content streamsto magnetic disk media that substantially addresses the above-identifiedneeds as well as others. One embodiment provides a method with which torecord simultaneous content streams to magnetic disk media. Thisinvolves receiving a first content stream via a first channel andreceiving a second content stream via a second channel. A firstread-write (RW) head of a multiple RW head system may be reserved orpreferentially assigned to the first channel. Similarly, a second RWhead of a multiple RW head disk drive may be reserved or preferentiallyassigned to the second channel. Memory locations (contiguous locationsor blocks within the magnetic disk media) are identified that areoperable to store the first and second content stream after which the RWheads are used to write the first and second content stream to disk.

Yet another embodiment provides a disk controller operable to affectefficient storage and retrieval of multiple content (data) streams tomagnetic disk media. This disk controller includes an interface module,a memory module, and a processing module. The interface module isoperable to couple the disk controller to a hard disk drive. The memorymodule and processing module in combination are operable to executeinstructions that detect the geometry associated with the hard diskdrive. Then the disk controller is operable to determine when the harddisk drive geometry supports assigning unique RW heads to unique content(data) streams. When the hard disk geometry supports assigning unique RWheads to unique content (data) streams, RW heads may be preferentiallyreserved or assigned to unique content streams wherein the RW heads areable to write unique content streams to memory locations within the harddisk drive, wherein these memory locations within the disk media may becontiguous or near contiguous.

Other embodiments of the present invention may include a hard driveoperable to record and retrieve simultaneous content streams to diskthat reduces fragmentation and may extend the product lifetimeassociated with the magnetic disk media. Yet other embodiments mayinclude content recorders that may utilize hard disk drives or diskcontrollers to efficiently store simultaneous content (data) streams.

FIG. 2 depicts a storage system used to record and retrieve multiplecontent (data) streams to magnetic media. This system includes a host20, disk controller 22 and magnetic media 24. Host 20 may be a set topbox or other multimedia device operable to receive multiple incomingstreams of multimedia shown as inputs “A” and “B” to the host. Forexample, when host 20 is embodied as a set top box or digital videorecorder (DVR), this set top box may receive multiple inputs such as theoutput of an audio/video receiver, television receiver, satellite tunerreceiver, other multimedia receiver, or preprocessed multimedia signals.Host 20 is operable to select the content streams to be stored. Forexample, a first and second channel shown here as channel A and channelB may be selected by the host and supplied to disk controller 22 forstorage. Disk controller 22 then directs the storage of the streamedcontent from channels A and channel B onto magnetic media 24. Eachcontent (data) stream contains data which may be best accessed from acontiguous location on the disk. However, since the data from two ormore streams is multiplexed, the data may be stored as a series of datacomponents A₁B₁A₂B₂A₃B₃ . . . in a single location. When the contentfrom one channel is deleted, fragmentation occurs and can furthercomplicate the storage of additional data. This situation is representedby the data chain A₁ _(—) A₂ _(—) A₃ _(—) . . . where the contents ofchannel B have been deleted. Most applications multiplex data toavailable magnetic media as most applications are blind to the internalgeometry and organization of the disk data. As illustrated, this canresult in severe fragmentation when the content associated with one datastream is erased in favor of that from a newer data stream. However,this type of solution minimizes the movement of the RW head within thedisk drive. The performance of the hard drive is limited as content iswritten to or retrieved from a fragmented disk location.

FIG. 3 provides a second solution where the content (data) stream forchannel A and channel B are written to contiguous but distinct locationswithin the magnetic media. However, simultaneous recording of multimediafiles or content streams will cause the RW head of the disk drive, tomove excessively in a zigzag pattern 26 as shown. Excessive movement maycause excessive wear, noise, reduced performance, and limit the overalllifetime of the magnetic media 24 and disk drive that the magnetic mediais contained within. For example, excessive noise from a host device orset top box may distract from the viewing experience. Additionally, whenthe set top box is recording a stream for later use, the reduced noiseallows the stream content to be recorded silently. Embodiments of thepresent invention may reduce the noise associated with consumerappliances. This solution offers an improvement with respect tofragmentation but the mechanical wear on the disk drive itself may beexcessive.

FIG. 4 depicts a hard disk drive 21 that includes disk controller 22,hard disk (magnetic media) 10, actuator 28, RW head 30 and positioningarm 32. Disk controller 22 as shown in FIG. 5 includes an interfacemodule 34, processing module 36 and memory module 38. Disk controller22, which may be implemented as an integrated circuit or series ofdiscrete components, may interface with host system 20 and direct theoperation of the other internal components within hard disk drive 21.

Processing module 36 may be a single processing device or a plurality ofprocessing devices. Such a processing device may be a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. Memory module 65 may takethe form of a single memory device or a plurality of memory devices.Such a memory device may be a read-only memory, random access memory,volatile memory, non-volatile memory, static memory, dynamic memory,flash memory, cache memory, and/or any device that stores digitalinformation. Note that when the Disk controller 22 implements one ormore of its functions via a state machine, analog circuitry, digitalcircuitry, and/or logic circuitry, the memory storing the correspondingoperational instructions may be embedded within, or external to, thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. Processing module 36 stores andexecutes operational instructions corresponding to at least some of thesteps and/or functions illustrated with reference to FIGS. 10 and 11.

Disk controller 22 may determine and track the disk geometry associatedwith the hard disk drive. The geometry includes both the number ofavailable platters (disk surfaces) and RW heads within the hard diskdrive. FIG. 6 depicts a multi-disk hard disk drive 40 having disks 42,44 and 46. Each disk may have an available upper surface (platter) andlower surface. RW heads 48, 50, 52, 54, 56 and 58. In thismultiple-head, multiple-disk system disk controller 22 may execute aprotocol layer operable to reserve a particular head, 48 through 58, toa particular channel or input. In one embodiment, disk drive 40 may beconfigured with multiple disks 42, 44 and 46 having about 80 availablegigabytes per platter. By assigning an individual head or group of headsto an individual channel or content stream, the problem of recordingstreamed content from a single channel to a contiguous memory locationmay be addressed.

The individual heads are mounted to arms that the actuator positions asa group. Thus, typical configurations do not allow each RW head to beindependently positioned. However, other embodiments are envisionedwhere RW heads may be positioned independently or where more than oneindependently controlled RW head is assigned to a platter. Where the RWheads do not move independently, the disk controller may examine theavailable space on the top and bottom side of each disk within the harddisk drive. Then, the disk controller can determine whether or notsufficient contiguous disk space is available to store the two separatecontent streams within a cylinder of the disk drive. Where each contentstream is stored to a separate platter.

For illustrative purposes, FIG. 7 show the content from channel “A”written to the upper platter of disk 42 and content from channel “B”written to the upper platter of disk 44, wherein the content fromchannels “A” and “B” are written to the same cylinder of the hard diskdrive. Thus, the content from channel “A” may be written to a contiguouslocation on disk 42 while the content from channel “B” may be written toa contiguous location on disk 44. RW head movement may be dramaticallyreduced as the actuator need not continuously radially reposition the RWheads between cylinders during the recording or retrieval of a contentstream or file. Additionally, the life of the magnetic media may beimproved by reducing wear as content typically does not becomefragmented and require as much defragmentation processing in order todefragment previously recorded content following the removal of othercontent. By reducing or radial movement between tracks or diskcylinders, noise associated with the device may be greatly reduced. Forhome appliances, this improves the user experience.

By preferentially reserving a RW head to a content stream, fragmentationand radial RW head movement while writing or retrieving content isreduced. Additional improvements may include the ability to provideindependent radial movement for each head or a set of heads therebyfurther improving the ability of the disk controller to identifycontiguous locations on which the content of a channel may be stored.

FIG. 8 provides a functional block diagram of a system operable toreserve individual read/write heads for particular channels. Here host80 will receive data from multiple content streams such as channel “A”and channel “B”. This content is provided to a hard drive 86 within orcoupled to the set top box. First channel input 82 may receive a firstcontent stream such as that provided by channel “A”; while a secondchannel input 84 may receive a second content stream such as thatprovided by channel “B”. Disk controller 88 will determine whether ornot the hard drive 86 contains and supports multiple heads and thatsufficient contiguous space is available on disks 90 such thatindividual heads may be assigned to individual channels. Thisdetermination is made by disk controller 88 examining the geometry ofthe disk and currently stored data within the disk. Should the disk becapable of utilizing multiple heads to write data, wherein individualheads are assigned to individual channels, the disk controller willpreferentially assign a RW head to a specific channel and write thatcontent to a single platter within disks 90. These disk locations, thelocations for channel A and channel B may be on different platters,different faces of individual platters, or within the same platterdepending on the head and geometry of the disk drive. For example,should a disk drive have multiple RW heads available for an individualplatter, content streams may be recorded to radially separate tracks.Additionally, disk controller 88 is operable to determine when a needexists to defragment stored content and rewrite that content tocontiguous or near contiguous memory locations within the disk media.

FIG. 9 provides a functional block diagram of a content recorder 100 inaccordance with an embodiment of the present invention. Content recorder100 includes a first tuner 102, a second tuner 104, host 80, firstchannel input 82, second channel input 86, and a hard disk drive 86.Although tuners 102 and 104 are depicted as providing channels “A” and“B”, an audio/video (AV) signal or other like signal may be provided tothe inputs 82 and 84. Hard disk drive 86 further includes a diskcontroller 88, magnetic media (disks) 90 and RW heads 92 and 94. contentrecorder 100 Multimedia controller 80 will receive data in the form of adata stream channel A and a data stream channel B which are received atthe first channel input 84 and second channel input 86, respectively.This data is directed by host controller 82 to be stored for retrievalon hard drive 90. The disk controller within hard drive 90 couples toand receives the first content stream and second content stream fromfirst channel input 84 and second channel input 86. The disk controllerdetermines when and if multiple RW heads 92 and 94 are available towrite simultaneous streams to disk 90. Typically, this function may havebeen performed by the host device and not the disk controller. Bydelegating this task when possible to the disk controller, the processorwithin the host device is available to perform other tasks. If thehardware configuration of the hard disk drive and the available memorylocations within the disk(s) allow multiple RW heads to be assigned towrite simultaneous content streams to disk, then the disk controllerwill reserve a first RW head to the first content stream and reserve asecond RW head to the second content stream. Then the disk controllerhaving determined a first and second memory location operable to storethe first and second content, will direct that the content be stored inthese locations.

FIG. 10 is a logic flow diagram depicting a method operable to storesimultaneous content streams to memory in accordance with an embodimentof the present invention. This involves in first step 112 receiving afirst content stream. A second content stream is received in step 114. Adisk controller associated with a hard drive to which the content streamwill be stored will determine the geometry on the hard drive at setpoint 116. Determining the geometry of the hard drive will involve bothdetermining the number of RW heads that are available and thegeometrical location of contiguous memory storage locations available onthe individual disks within the hard drive. In step 118, the diskcontroller determines, based on the geometry of the hard drive, theavailability of a first memory location within the disk media operableto store the first content stream. Similarly, step 120 determines theavailability of a second memory location within the disk media operableto store the second content stream. At decision point 122, adetermination is made as to whether or not the hardware configurationsupports multiple heads and whether or not the geometry of the availablememory locations within the disk media supports the implementation. Ifeither the availability of heads or the availability of disk space isnot available, then step 124 will write the content of both streams tomemory using a standard storage algorithm. Otherwise, when the geometryof the hard drive supports a multiple head configuration, the diskcontroller will determine the best memory locations based on multiplehead access with lowest fragmentation and head/track movement. Then instep 126, a first head will be assigned or reserved to the firstchannel. In step 128, a second head, an additional head, will beassigned to the second channel. Then in step 130, the contents of thefirst content stream and the second content stream are written to diskusing the first and second RW heads.

FIG. 11 provides the second logic flow diagram wherein the diskcontroller within embodiments of the present invention is operable toimprove the availability of memory locations within the hard drive inorder to support multiple head access. In step 140, the disk controllerwill examine the hardware configuration and geometry associated with thememory of the contents written to disk. If necessary in step 142, thememory will be defragmented such that individual content files, such asmultimedia files, are stored in contiguous memory locations. At decisionpoint 144 a determination will be made whether or not it is necessary tofurther defragment the disk media. For example, if content is stored ina contiguous or near contiguous disk location, but written in ascattered manner within the disk location, disk performance may beimproved by reorganizing the content within the contiguous disklocation. If not, in step 146 the geometry information associated withthe hard drive is verified and supplied to the disk controller. Ifhowever, further reorganization of the content is required at decisionpoint 144, the reorganization and defragmentation process of the disk isperformed in step 148. Afterwards, the geometry information associatedwith the hard drive is updated to the disk controller in step 150. Thishelps to ensure that the memory in the hard drive is configured in orderto best support multiple head access. Supporting multiple head accessimproves the overall performance of the hard drive.

During the defragmentation process, the disk controller may write datatemporarily to memory accessible to the disk controller. This may reduceor eliminate the need to use memory available through a host device tosupport the defragmentation process. This reduces communicating betweenthe host device and hard drive and further allows the host device toperform other tasks.

In summary, embodiments of the present invention provide disk controlleroperable to facilitate the efficient storage and retrieval of multiplecontent (data) streams to magnetic disk media. This disk controllerincludes an interface module, a memory module, and a processing module.The interface module is operable to couple the disk controller to a harddisk drive. The memory module and processing module in combination areoperable to execute instructions that detect the geometry associatedwith the hard disk drive. Then the disk controller is operable todetermine when the hard disk drive geometry supports assigning unique RWheads to unique content (data) streams. When the hard disk geometrysupports assigning unique RW heads to unique content (data) streams, RWheads may be preferentially reserved or assigned to unique contentstreams wherein the RW heads are able to write unique content streams tomemory locations within the hard disk drive, wherein these disklocations may be contiguous or near contiguous.

As one of average skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term. Such anindustry-accepted tolerance ranges from less than one percent to twentypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. As one of average skill in the artwill further appreciate, the term “operably coupled”, as may be usedherein, includes direct coupling and indirect coupling via anothercomponent, element, circuit, or module where, for indirect coupling, theintervening component, element, circuit, or module does not modify theinformation of a signal but may adjust its current level, voltage level,and/or power level. As one of average skill in the art will alsoappreciate, inferred coupling (i.e., where one element is coupled toanother element by inference) includes direct and indirect couplingbetween two elements in the same manner as “operably coupled”. As one ofaverage skill in the art will further appreciate, the term “comparesfavorably”, as may be used herein, indicates that a comparison betweentwo or more elements, items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1.

Although the present invention is described in detail, it should beunderstood that various changes, substitutions and alterations can bemade hereto without departing from the spirit and scope of the inventionas described by the appended claims.

1. A storage device, comprising: a first channel input operable toreceive a first content stream streamed to a host device coupled to thestorage device via a first channel; a second channel input operable toreceive a second content stream streamed simultaneous to the firstcontent stream to the host device via a second channel; a magnetic diskmedia operable to store content streams; a first read/write (RW) head; asecond RW head; and a disk controller coupled to the first channelinput, the second channel input, the first RW head, and the second RWhead, wherein the disk controller is operable to: determine a first disklocation on the magnetic disk media to store the first content stream,the first disk location comprising a plurality of substantiallycontiguous data blocks; determine a second disk location on the magneticdisk media to store the second content stream, the second disk locationcomprising a plurality of substantially contiguous data blocks; andwrite the first content stream to the first disk location using thefirst RW head and the second content stream to the second memory diskusing the second RW head.
 2. The storage device of claim 1, wherein thestorage device is a hard drive and the magnetic disk media includes atleast one platter.
 3. The storage device of claim 2, wherein the firstRW head is assigned to an upper face of the at least one platter, andthe second RW head is assigned to a lower face of the at least oneplatter.
 4. The storage device of claim 3, wherein the first RW head andsecond RW head are operable to be independently positioned within thehard drive.
 5. The storage device of claim 3, wherein the diskcontroller is operable to write the first content stream and the secondcontent stream to another data block using a standard storage algorithmwhen at least one of the first RW head and the second RW head is notavailable.
 6. The storage device of claim 5, wherein the disk controlleris operable to: defragment the first content stream and the secondcontent stream to near contiguous respective disk locations afterwriting the first content stream and the second content stream to theanother data block using the standard storage algorithm.
 7. A storagesystem, comprising: a host device including a first channel inputoperable to receive a first content stream streamed thereto via a firstchannel and a second channel input operable to receive a second contentstream streamed simultaneous to the first content stream thereto via asecond channel; a magnetic disk media operable to store content streams;and a disk controller coupled to the host device and the magnetic diskmedia, wherein the disk controller is operable to: determine a firstdisk location on the magnetic disk media operable to store the firstcontent stream, the first disk location comprising a plurality ofsubstantially contiguous data blocks; determine a second disk locationon the magnetic disk media operable to store the second content stream,the second disk location comprising a plurality of substantiallycontiguous data blocks, wherein the first disk location and second disklocation are based on multiple head access to the first disk locationand second disk location; and write the first content stream to thefirst disk location and the second content stream to the second disklocation.
 8. The storage system of claim 7, further comprising: a firsttuner operable to provide the first content stream to the first channelinput; and a second tuner operable to provide the second content streamto the second channel input.
 9. The storage system of claim 7, furthercomprising: a multiple RW head memory system including a firstread/write (RW) head operable to write the first content stream to thefirst disk location and a second read/write (RW) head operable to writethe second content stream to the second disk location.
 10. The storagesystem of claim 9, wherein the magnetic disk media is a hard disk drivethat includes at least one platter and the first RW head is assigned toan upper face of the at least one platter, and the second RW head isassigned to a lower face of the at least one platter.
 11. The storagesystem of claim 9, wherein the first RW head and second RW head areoperable to be independently positioned.
 12. The storage system of claim7, wherein the disk controller is operable to write the first contentstream and the second content stream to another data block when multipleRW heads are not available.
 13. The storage system of claim 12, whereinthe disk controller is operable to: defragment the first content streamand the second content stream to near contiguous respective disklocations after writing the first content stream and the second contentstream to the another data block.
 14. The storage system of claim 7,wherein the host device is a multimedia device.
 15. A disk controller,comprising: an interface coupled to a hard disk drive; a memory; and aprocessing device coupled to the memory, wherein a combination of theprocessing device and the memory is operable to execute instructionsthat: reserve a first read/write (RW) head of a multiple RW head memorysystem coupled to the hard disk drive to a first content stream streamedto a host device coupled to the disk controller via a first channel;reserve a second RW head of the multiple RW head memory system to asecond content stream streamed simultaneous to the first content streamto the host device via a second channel; write the first content streamto a first disk location in the hard disk drive with the first RW head,the first disk location comprising a plurality of substantiallycontiguous data blocks; and write the second content stream to a seconddisk location in the hard disk drive with the second RW head, the seconddisk location comprising a plurality of substantially contiguous datablocks.
 16. The disk controller of claim 15, wherein the combination ofthe processing device and the memory is further operable to executeinstructions that: detect a geometry associated with the hard diskdrive, and wherein both the first RW head and the second RW head arereserved when the hard disk drive geometry supports assigning unique RWheads to unique content streams.
 17. The disk controller of claim 15,wherein the first disk location and the second disk location are withina cylinder of the hard disk drive.
 18. The disk controller of claim 15,wherein the disk controller is implemented as an integrated circuit. 19.A method for storing simultaneous content streams to magnetic diskmedia, comprising: receiving a first content stream streamed to a hostdevice coupled to the magnetic disk media via a first channel; receivinga second content stream streamed simultaneous to the first contentstream to the host device via a second channel; determining a first disklocation on the magnetic disk media operable to store the first contentstream, the first disk location comprising a plurality of substantiallycontiguous data blocks; determining a second disk location on themagnetic disk media operable to store the second content stream, thesecond disk location comprising a plurality of substantially contiguousdata blocks, wherein the first disk location and the second disklocation are based on multiple head access to the first disk locationand the second disk location; and writing the first content stream tothe first disk location and the second content stream to the second disklocation.
 20. The method of claim 19, further comprising: reserving afirst read/write (RW) head of a multiple RW head memory system for thefirst channel; and reserving a second RW head of the multiple RW headmemory system for the second channel.